The objective of this project is to determine the function of select members of the ADAM family of proteins during morphogenesis and differentiation of the neural crest. This research project will utilize chick embryos and will test the hypothesis that ADAM family members regulate certain aspects of neural crest cell morphogenesis and differentiation. The ADAM proteins contain several extracellular domains including metalloprotease, disintegrin, and cysteine-rich, and are transmembrane proteins. This project will examine the ADAM family members expressed in neural crest cells, which are a transient cell population that give rise to the peripheral nervous system, structures of the eye, and pigment cells, among other tissues. Antifunctional antibodies and antisense oligonucleotides will be applied in vivo and in vitro to inhibit ADAM protein function, to determine the importance of ADAM proteins during neural crest cell migration and differentiation.